This note begins a series of notes on application development and deployment processes. To start with, I will show how you can relatively easily implement a code quality and functionality checking process using the Travis CI service.

The practice of continuously checking the build for defects is called Continuous Integration.

The question of writing tests will not be addressed in this article - it is the subject of another article. It is assumed that you have already set up Behat, and the tests can already be run locally using Selenium.

To begin with, let's check if there are any rule violations in the code. This will allow you to familiarize yourself with and start using Travis CI. If you don't have any tests, I strongly recommend at least checking the code style.
The justification for the importance of code consistency and style can be found in many places, for example, Steve McConnell's "Code Complete", part 7, section 31.